Production Of Polyunsaturated Fatty Acids Research Articles

Integrated Transcriptome and Metabolome Analysis Revealed the Causal Agent of Primary Bud Necrosis in 'Summer Black' Grape.

Primary bud necrosis of grape buds is a physiological disorder that leads to decreased berry yield and has a catastrophic impact on the double cropping system in sub-tropical areas. The pathogenic mechanisms and potential solutions remain unknown. In this study, the progression and irreversibility patterns of primary bud necrosis in 'Summer Black' were examined via staining and transmission electron microscopy observation. Primary bud necrosis was initiated at 60 days after bud break and was characterized by plasmolysis, mitochondrial swelling, and severe damage to other organelles. To reveal the underlying regulatory networks, winter buds were collected during primary bud necrosis progression for integrated transcriptome and metabolome analysis. The accumulation of reactive oxygen species and subsequent signaling cascades disrupted the regulation systems for cellular protein quality. ROS cascade reactions were related to mitochondrial stress that can lead to mitochondrial dysfunction, lipid peroxidation causing damage to membrane structure, and endoplasmic reticulum stress leading to misfolded protein aggregates. All these factors ultimately resulted in primary bud necrosis. Visible tissue browning was associated with the oxidation and decreased levels of flavonoids during primary bud necrosis, while the products of polyunsaturated fatty acids and stilbenes exhibited an increasing trend, leading to a shift in carbon flow from flavonoids to stilbene. Increased ethylene may be closely related to primary bud necrosis, while auxin accelerated cell growth and alleviated necrosis by co-chaperone VvP23-regulated redistribution of auxin in meristem cells. Altogether, this study provides important clues for further study on primary bud necrosis.

Oxylipin secretion by human CD3+ T lymphocytes in vitro is modified by the exogenous essential fatty acid ratio and life stage.

Immune function changes across the life stages; for example, senior adults exhibit a tendency towards a weaker cell-mediated immune response and a stronger inflammatory response than younger adults. This might be partly mediated by changes in oxylipin synthesis across the life course. Oxylipins are oxidation products of polyunsaturated fatty acids (PUFAs) that modulate immune function and inflammation. A number of PUFAs are precursors to oxylipins, including the essential fatty acids (EFAs) linoleic acid (LA) and α-linolenic acid (ALA). LA and ALA are also substrates for synthesis of longer chain PUFAs. Studies with stable isotopes have shown that the relative amounts of LA and ALA can influence their partitioning by T lymphocytes between conversion to longer chain PUFAs and to oxylipins. It is not known whether the relative availability of EFA substrates influences the overall pattern of oxylipin secretion by human T cells or if this changes across the life stages. To address this, the oxylipin profile was determined in supernatants from resting and mitogen activated human CD3+ T cell cultures incubated in medium containing an EFA ratio of either 5:1 or 8:1 (LA : ALA). Furthermore, oxylipin profiles in supernatants of T cells from three life stages, namely fetal (derived from umbilical cord blood), adults and seniors, treated with the 5:1 EFA ratio were determined. The extracellular oxylipin profiles were affected more by the EFA ratio than mitogen stimulation such that n-3 PUFA-derived oxylipin concentrations were higher with the 5:1 EFA ratio than the 8:1 ratio, possibly due to PUFA precursor competition for lipoxygenases. 47 oxylipin species were measured in all cell culture supernatants. Extracellular oxylipin concentrations were generally higher for fetal T cells than for T cells from adult and senior donors, although the composition of oxylipins was similar across the life stages. The contribution of oxylipins towards an immunological phenotype might be due to the capacity of T cells to synthesize oxylipins rather than the nature of the oxylipins produced.

Harmonization of OF LC‐MS oxylipin analysis to investigate lipid mediator formation and signaling in immune cells

The oxidation products of polyunsaturated fatty acids (PUFA) ‐ oxylipins ‐ are formed via enzymatic conversion by cyclooxygenases, lipoxygenases (LOX) and cytochrome P450 monooxygenases or by autoxidation. Together with multiple PUFA substrates this leads to a large variety of oxylipins, whose physiological functions are ‐ besides those of well‐studied prostaglandins and leukotrienes ‐ little understood. The interplay of several PUFA‐oxidizing enzymes, as in the case of multihydroxylated oxylipins, additionally complicates the investigation of their biosynthesis. Due to regulatory crosstalk and complex interactions of different oxylipin classes during physiological processes, such as inflammation, a study of the whole oxylipin profile rather than individual compounds is necessary. Therefore, in order to understand the functions of these lipid mediators potent and reliable biochemical methods and (molecular) biological models are required, in combination with sensitive and sound preanalytical, analytical and post‐analytical procedures for their investigation.The first part of this thesis investigated the relevance of harmonizing such analytical methods for the quantitative determination of oxylipins in biological samples. Based on the outcome of an international laboratory comparison, comparable and reproducible results were obtained across independent laboratories when these harmonized methods were used for sample preparation and analysis by means of liquid chromatography coupled with tandem mass spectrometry. The examination of the effect of different storage times and temperatures as a parameter of pre‐analytics demonstrated that oxylipin levels in plasma samples are robust to long‐term storage and, furthermore, to minor variations during plasma generation. As accurate quantification of oxylipin concentrations rises and falls with the quality of analytical standards, a strategy for the verification of oxylipin standard concentrations with mass‐ spectrometry and UV spectroscopy based approaches using certified standard compounds was presented.In the second part of the thesis the established methods were applied to study the biosynthesis of oxylipins in immune cells with a special attention to the involved LOX. Stimulation of primary human M2‐like macrophages with the liver X receptor (LXR) agonist T09 led to a massive induction of ALOX15 gene expression and thus, 15‐LOX abundance and activity. Cholesterol derivatives were identified as potent endogenous ligands of LXR yielding increased 15‐LOX abundance and activity. The examination of 5‐LOX induced synthesis of multihydroxylated metabolites through supplementation of neutrophils with 15‐HETE, 18‐ HEPE and 17‐HDHA primary leads to formation of double oxygenated oxylipins. In intact cells 5‐LOX preferred DHA‐derived 17‐HDHA as substrate, whereas upon cell integrity destruction the formation of 15‐HETE derived multihydroxylated oxylipins increased.With the combination of harmonized protocols for sampling and analysis this thesis sets the basis for the reliable quantification of oxylipins. The use of the optimized methodologies allowed to further characterize regulatory pathways of the ARA cascade in human immune cells, contributing to a more thorough understanding of inflammation regulation.

Bioprocess engineering to produce essential polyunsaturated fatty acids from Thraustochytrium sp.

In recent studies, thraustochytrid has emerged as a sustainable substitute to fish oil or polyunsaturated fatty acid (PUFA) sources: docosapentaenoic acid (DPA) eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Due to growing health concerns, there is increasing demand for food and health applications of PUFA for several diseases, aquaculture feeds, and dietary products. Thraustochytrium sp. found a sustainable source for considerable PUFA and SFA production and to meet omega PUFA demand globally. This study aims to increase PUFA yield by the maximum possible glucose carbon with an appropriate nitrogen ratio (10:1). The maximum biomass and lipid obtained from 40 g/L glucose, were 7.47 ± 0.3 g/L and 4.63 g/L (60.84 ± 1.4%), respectively. However, maximum relative lipid, DHA and DPA yields were from 30 g/L glucose i.e, 67.6 ± 1.9 % and 963.58 ± 24 and 693.10 ± 24 mg/L respectively with complete glucose assimilation. Thus, this could be a potential source of commercial DPA and DHA producers under the biorefinery scheme.

Characterization of nongxiang- and soy sauce-type distilled grains and their application in enhancing polyunsaturated fatty acid and triacylglyceride production from Chlorella sp. 038F

A sustainable method of handling large quantities of distilled grains in the Chinese baijiu industry is bioconverting these distilled grains into value-added products. We here compared the properties of two distilled grains, soy sauce-type (DGSB) and nongxiang-type (DGNB). Results revealed that DGSB had higher contents of crude protein, crude fat, soluble sugars, free amino acids, and antioxidants than DGNB. Mixotrophic cultivation of Chlorella sp. 038F was performed using aqueous crude extracts of distilled grains. Biomass, total lipid, and fatty acid production with DGSB crude extracts was approximately 2.43, 1.40, and 1.69 times higher than that with photoautotrophic culture, respectively, whereas DGNB crude extracts only improved the biomass by 1.64 times. Detailed profile analysis revealed that DGSB crude extracts remarkably increased the proportions of polyunsaturated fatty acids, especially linoleic and α-linolenic acids, and triacylglycerides in total lipids. Interestingly, DGNB crude extracts did not enhance total lipid accumulation but increased triacylglyceride accumulation. Comparative transcriptomics revealed that genes encoding photosynthetic pigments and proteins were downregulated, suggesting the decreased anabolism of the photosynthetic light reaction. Genes involved in fatty acid biosynthesis, the Calvin cycle, and glycolysis were upregulated, indicating sufficient accumulation of the building blocks acyl-CoA and glycerol-3-phosphate for triacylglyceride biosynthesis. All transcriptional trends of triacylglyceride biosynthesis-related genes were consistent with the triacylglyceride accumulation patterns. This study provides insights into the potential use of microalgae for the bioconversion of distilled grains into high-value products and highlights the role of distilled grains in improving polyunsaturated fatty acid and triacylglyceride production.

Bioactives Overproduction through Operational Strategies in the Ichthyotoxic Microalga Heterosigma akashiwo Culture.

The red tide-forming microalga Heterosigma akashiwo has been associated with massive events of fish deaths, both wild and cultured. Culture conditions are responsible for the synthesis or accumulation of some metabolites with different interesting bioactivities. H. akashiwo LC269919 strain was grown in a 10 L bubble column photobioreactor artificially illuminated with multi-coloured LED lights. Growth and production of exopolysaccharides, polyunsaturated fatty acids (PUFAs), and carotenoids were evaluated under different culture modes (batch, fed-batch, semicontinuous, and continuous) at two irradiance levels (300 and 700 µE·s-1·m-2). Continuous mode at the dilution rate of 0.2·day-1 and 700 µE·s-1·m-2 provided the highest production of biomass, PUFAs (132.6 and 2.3 mg·L-1·day-1), and maximum fucoxanthin productivity (0.16 mg·L-1·day-1). The fed-batch mode accumulated exopolysaccharides in a concentration (1.02 g·L-1) 10-fold over the batch mode. An extraction process based on a sequential gradient partition with water and four water-immiscible organic solvents allowed the isolation of bioactive fucoxanthin from methanolic extracts of H. akashiwo. Metabolites present in H. akashiwo, fucoxanthin and polar lipids (i.e., eicosapentaenoic acid (EPA)), or probably such as phytosterol (β-Sitosterol) from other microalgae, were responsible for the antitumor activity obtained.

Potential of Mortierellaceae for polyunsaturated fatty acids production: mini review.

The health benefits of polyunsaturated fatty acids (PUFAs) have encouraged the search for rich sources of these compounds. However, the supply chain of PUFAs from animals and plants presents environmental concerns, such as water pollution, deforestation, animal exploitation and interference in the trophic chain. In this way, a viable alternative has been found in microbial sources, mainly in single cell oil (SCO) production by yeast and filamentous fungi. Mortierellaceae is a filamentous fungal family world-renowned for PUFA-producing strains. For example, Mortierella alpina can be highlighted due to be industrially applied to produce arachidonic acid (20:4 n6), an important component of infant supplement formulas. Thus, the state of the art of strategies to increase PUFAs production by Mortierellaceae strains is presented in this review. Firstly, we have discussed main phylogenetic and biochemical characteristics of these strains for lipid production. Next, strategies based on physiological manipulation, using different carbon and nitrogen sources, temperature, pH and cultivation methods, which can increase PUFA production by optimizing process parameters are presented. Furthermore, it is possible to use metabolic engineering tools, controlling the supply of NADPH and co-factors, and directing the activity of desaturases and elongase to the target PUFA. Thus, this review aims to discuss the functionality and applicability of each of these strategies, in order to support future research for PUFA production by Mortierellaceae species.

Assessment of thraustochytrids potential for carotenoids, terpenoids and polyunsaturated fatty acids biorefinery.

Heterotrophic fast-growing thraustochytrids have been identified as promising candidates for the bioconversion of organic sources into industrially important valuable products. Marine thraustochytrids exhibit remarkable potential for high-value polyunsaturated fatty acids (PUFAs) production however their potential is recently discovered for high-value carotenoids and terpenoids which also have a role as a dietary supplement and health promotion. Primarily, omega-3 and 6 PUFAs (DHA, EPA, and ARA) from thraustochytrids are emerging sources of nutrient supplements for vegetarians replacing animal sources and active pharmaceutical ingredients due to excellent bioactivities. Additionally, thraustochytrids produce reasonable amounts of squalene (terpenoid) and carotenoids which are also high-value products with great market potential. Hence, these can be coextracted as a byproduct with PUFAs under the biorefinery concept. There is still quite a few printed information on bioprocess conditions for decent (co)-production of squalene and carotenoid from selective protists such as lutein, astaxanthin, canthaxanthin, and lycopene. The current review seeks to provide a concise overview of the coproduction and application of PUFAs, carotenoids, and terpenoids from oleaginous thraustochytrids and their application to human health.

Transcriptome Analysis Reveals an Eicosapentaenoic Acid Accumulation Mechanism in a Schizochytrium sp. Mutant.

Eicosapentaenoic acid (EPA) is an omega-3 long-chain polyunsaturated fatty acid (PUFA) essential for human health. Schizochytrium is a marine eukaryote that has been widely utilized for the synthesis of PUFAs. The current low potency and performance of EPA production by fermentation of Schizochytrium spp. limits its prospect in commercial production of EPA. Since the synthesis pathway of EPA in Schizochytrium spp. is still unclear, mutagenesis combined with efficient screening methods are still desirable. In this study, a novel screening strategy was developed based on a two-step progressive mutagenesis method based on atmospheric and room temperature plasma (ARTP) and diethyl sulfate (DES) after multiple stresses (sethoxydim, triclosan and 2,2'-bipyridine) compound screening. Finally, the mutant strain DBT-64 with increased lipid (1.57-fold, 31.71 g/L) and EPA (5.64-fold, 1.86 g/L) production was screened from wild-type (W) strains; the docosahexaenoic acid (DHA) content of mutant DBT-64 (M) was 11.41% lower than that of wild-type strains. Comparative transcriptomic analysis showed that the expression of genes related to the polyketide synthase, fatty acid prolongation, and triglyceride synthesis pathways was significantly upregulated in the mutant strain, while the expression of genes involved in the β-oxidation pathway and fatty acid degradation pathway was downregulated in favor of EPA biosynthesis in Schizochytrium. This study provides an effective strain improvement method to enhance EPA accumulation in Schizochytrium spp. IMPORTANCE Schizochytrium, a marine eukaryotic microorganism, has emerged as a candidate for the commercial production of PUFAs. EPA is an omega-3 PUFA with preventive and therapeutic effects against cardiovascular diseases, schizophrenia, and other disorders. Currently, the low potency and performance of EPA production by Schizochytrium spp. limits its commercialization. In this study, we performed two-step progressive mutagenesis based on ARTP and DES and screened multiple stresses (sethoxydim, triclosan, and 2,2'-bipyridine) to obtain the EPA-high-yielding Schizochytrium mutant. In addition, high expression of the polyketide synthase pathway, fatty acid elongation pathway, and triglyceride synthesis pathway in the mutants was confirmed by transcriptomic analysis. Therefore, the multistress screening platform established in this study is important for breeding EPA-producing Schizochytrium spp. and provides valuable information for regulating the proportion of EPA in microalgal lipids by means of genetic engineering.

Protective Effect of Apple Polyphenols on H2O2-Induced Oxidative Stress Damage in Human Colon Adenocarcinoma Caco-2 Cells.

Apple is an important dietary agent for human and apple polyphenols (AP) are the main secondary metabolites of apples. In this study, the protective effects of AP on hydrogen peroxide (H2O2)-induced oxidative stress damage in human colon adenocarcinoma Caco-2 cells were investigated by cell viability, oxidative stress change as well as cell apoptosis. Pre-adding AP could significantly increase the survival rate of H2O2-treated Caco-2 cells. Besides, the activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase (CAT) were elevated. While the malondialdehyde (MDA) content which is the major oxidant products of polyunsaturated fatty acids (PUFA) reduced after AP treatment. In addition, AP also suppressed the emergence of DNA fragment and decreased the expression of apoptosis-related protein Caspase-3. These results demonstrated that AP could ameliorate H2O2-induced oxidative stress damage in Caco-2 cells, which could serve as a reference for further studies of apple natural active products and deep study of the anti-oxidative stress mechanism.

Microalgal polyunsaturated fatty acids: Hotspots and production techniques.

Algae play a crucial role in the earth's primary productivity by producing not only oxygen but also a variety of high-value nutrients. One such nutrient is polyunsaturated fatty acids (PUFAs), which are accumulated in many algae and can be consumed by animals through the food chain and eventually by humans. Omega-3 and omega-6 PUFAs are essential nutrients for human and animal health. However, compared with plants and aquatic sourced PUFA, the production of PUFA-rich oil from microalgae is still in the early stages of exploration. This study has collected recent reports on algae-based PUFA production and analyzed related research hotspots and directions, including algae cultivation, lipids extraction, lipids purification, and PUFA enrichment processes. The entire technological process for the extraction, purification and enrichment of PUFA oils from algae is systemically summarized in this review, providing important guidance and technical reference for scientific research and industrialization of algae-based PUFA production.

Pretreatment of beechwood with polyoxometalate-based catalysts towards the production of polyunsaturated fatty acids by Crypthecodinium cohnii

In the present work, a novel OxiOrganosolv pretreatment was developed for the fractionation of beechwood. Τhe process employs a mixture of water and common organic solvents, polyoxometalate complexes (POMs) as homogeneous catalysts and O2 that acts as an oxidative agent enabling their regeneration. Due to their strong oxidizing ability and redox reversibility, POMs can achieve efficient biomass fractionation by catalyzing simultaneously hemicellulose hydrolysis and oxidation of lignin ether bonds that leads to its depolymerization, dissolution in the organic solvent and removal from the cellulose-rich pulp. According to the results, both commercially available phosphomolybdic acid (HPMo) and also the in-house produced Fe- and Cu- exchanged salts successfully promoted delignification and hemicellulose removal compared to the OxiOrganosolv pretreatment in the absence of catalyst. Most importantly, catalytic lignin depolymerization was achieved without the use of mineral acids that are typically used in a traditional organosolv. Evaluation of the enzymatic digestibility of the pulps revealed HPMo as the most favorable catalyst for increased saccharification yields and production of sugar-rich hydrolysates that were further used as carbon sources for fermentation and production of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) from the heterotrophic microalgae Crypthecodinium cohnii. Hydrolysates produced from HPMo and Fe-PMo-assisted OxiOrganosolv pretreatment supported cell growth and led to high accumulation of ω-3 PUFAs, while severe inhibition was observed with the hydrolysates from Cu-PMo pretreated biomass. This study demonstrates the possibility of using POMs as catalysts for efficient biomass delignification with the aim to obtain sugar-rich streams that can be utilized for the production of nutraceuticals.

Melanoma-associated repair-like Schwann cells suppress anti-tumor T-cells via 12/15-LOX/COX2-associated eicosanoid production

ABSTRACT Peripheral glia, specifically the Schwann cells (SCs), have been implicated in the formation of the tumor microenvironment (TME) and in cancer progression. However, in vivo and ex vivo analyses of how cancers reprogram SC functions in different organs of tumor-bearing mice are lacking. We generated Plp1-CreERT/tdTomato mice which harbor fluorescently labeled myelinated and non-myelin forming SCs. We show that this model enables the isolation of the SCs with high purity from the skin and multiple other organs. We used this model to study phenotypic and functional reprogramming of the SCs in the skin adjacent to melanoma tumors. Transcriptomic analyses of the peritumoral skin SCs versus skin SCs from tumor-free mice revealed that the former existed in a repair-like state typically activated during nerve and tissue injury. Peritumoral skin SCs also downregulated pro-inflammatory genes and pathways related to protective anti-tumor responses. In vivo and ex vivo functional assays confirmed immunosuppressive activities of the peritumoral skin SCs. Specifically, melanoma-reprogrammed SCs upregulated 12/15-lipoxygenase (12/15-LOX) and cyclooxygenase (COX)-2, and increased production of anti-inflammatory polyunsaturated fatty acid (PUFA) metabolites prostaglandin E2 (PGE2) and lipoxins A4/B4. Inhibition of 12/15-LOX or COX2 in SCs, or EP4 receptor on lymphocytes reversed SC-dependent suppression of anti-tumor T-cell activation. Therefore, SCs within the skin adjacent to melanoma tumors demonstrate functional switching to repair-like immunosuppressive cells with dysregulated lipid oxidation. Our study suggests the involvement of the melanoma-associated repair-like peritumoral SCs in the modulation of locoregional and systemic anti-tumor immune responses.

Saturated and Polyunsaturated Fatty Acids Production by Aurantiochytrium limacinum PKU#Mn4 on Enteromorpha Hydrolysate.

Thraustochytrids are unicellular marine heterotrophic protists, which have recently shown a promising ability to produce omega-3 fatty acids from lignocellulosic hydrolysates and wastewaters. Here we studied the biorefinery potential of the dilute acid-pretreated marine macroalgae (Enteromorpha) in comparison with glucose via fermentation using a previously isolated thraustochytrid strain (Aurantiochytrium limacinum PKU#Mn4). The total reducing sugars in the Enteromorpha hydrolysate accounted for 43.93% of the dry cell weight (DCW). The strain was capable of producing the highest DCW (4.32 ± 0.09 g/L) and total fatty acids (TFA) content (0.65 ± 0.03 g/L) in the medium containing 100 g/L of hydrolysate. The maximum TFA yields of 0.164 ± 0.160 g/g DCW and 0.196 ± 0.010 g/g DCW were achieved at 80 g/L of hydrolysate and 40 g/L of glucose in the fermentation medium, respectively. Compositional analysis of TFA revealed the production of equivalent fractions (% TFA) of saturated and polyunsaturated fatty acids in hydrolysate or glucose medium. Furthermore, the strain yielded a much higher fraction (2.61-3.22%) of eicosapentaenoic acid (C20:5n-3) in the hydrolysate medium than that (0.25-0.49%) in the glucose medium. Overall, our findings suggest that Enteromorpha hydrolysate can be a potential natural substrate in the fermentative production of high-value fatty acids by thraustochytrids.

An Environmentally Friendly Biosurfactant to Enhance the Enzymatic Hydrolysis for Production of Polyunsaturated Fatty Acids with Potential Application as Nutraceutical

An Environmentally Friendly Biosurfactant to Enhance the Enzymatic Hydrolysis for Production of Polyunsaturated Fatty Acids with Potential Application as Nutraceutical

Sex-Specific Response of the Brain Free Oxylipin Profile to Soluble Epoxide Hydrolase Inhibition.

Oxylipins are the oxidation products of polyunsaturated fatty acids and have been implicated in neurodegenerative disorders, including dementia. Soluble epoxide hydrolase (sEH) converts epoxy-fatty acids to their corresponding diols, is found in the brain, and its inhibition is a treatment target for dementia. In this study, male and female C57Bl/6J mice were treated with an sEH inhibitor (sEHI), trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), for 12 weeks to comprehensively study the effect of sEH inhibition on the brain oxylipin profile, and modulation by sex. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure the profile of 53 free oxylipins in the brain. More oxylipins were modified by the inhibitor in males than in females (19 versus 3, respectively) and favored a more neuroprotective profile. Most were downstream of lipoxygenase and cytochrome p450 in males, and cyclooxygenase and lipoxygenase in females. The inhibitor-associated oxylipin changes were unrelated to serum insulin, glucose, cholesterol, or female estrous cycle. The inhibitor affected behavior and cognitive function as measured by open field and Y-maze tests in males, but not females. These findings are novel and important to our understanding of sexual dimorphism in the brain's response to sEHI and may help inform sex-specific treatment targets.

Alternative microbial-based functional ingredient source for lycopene, beta-carotene, and polyunsaturated fatty acids

The acquisition of carotenoids and polyunsaturated fatty acids (PUFAs) from plants and animals for use as functional ingredients raises concerns regarding productivity and cost; utilization of microorganisms as alternative sources is an option. We proposed to evaluate the production of carotenoids and PUFAs by Rhodopseudomonas faecalis PA2 using different vegetable oils (rice bran oil, palm oil, coconut oil, and soybean oil) as carbon source, different concentrations of yeast extract as nitrogen source at different cultivation time to ensure the best production. Cultivation with soybean oil as source of carbon led to the most significant changes in the fatty acid profile. Compared to the initial condition, the strain cultivated in the optimal conditions (4% soybean oil, 0.35% yeast extract, and 14 days of incubation) showed an increase in μmax, biomass, carotenoid productivity, and microbial lipids by 102.5%, 52.7%, 33.82%, and 34.78%, respectively. The unsaturated fatty acids content was raised with additional types of PUFAs; omega-3 [alpha-linolenic acid and eicosapentaenoic acid] and omega-6 [linoleic acid and eicosatrienoic acid] fatty acids were identified. The results of ultra high-performance liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry (UHPLC-ESI-QTOF-MS/MS) indicated the molecular formula and mass of bacterial metabolites were identical to those of lycopene and beta-carotene. The untargeted metabolomics revealed functional lipids and several physiologically bioactive compounds. The outcome provides scientific reference regarding carotenoids, PUFAs, and useful metabolites that have not yet been reported in the species Rhodopseudomonas faecalis for further use as a microbial-based functional ingredient.

Health and nutrition claims for infant formula: international cross sectional survey

ObjectivesTo review available health and nutrition claims for infant formula products in multiple countries and to evaluate the validity of the evidence used for substantiation of claims.DesignInternational cross sectional survey.SettingPublic...

PUFAs dictate the balance of power in ferroptosis

Ferroptosis is an iron-dependent form of cell death triggered by dysregulation of biochemical processes that culminate in lethal lipid peroxidation. Lipid metabolism is fundamental for determining ferroptotic fate, however, the mechanisms that alter lipid components to shape ferroptosis susceptibility remains elusive. A recent article by Lin and colleagues in Nature Communications systematically analyzed phospholipid transporters (phospholipid scramblases, flippases, and floppases), and identified that the lipid flippase solute carrier family 47 member 1 (SLC47A1) functions as a regulator of lipid remodeling and promotes ferroptosis resistance. SLC47A1 is transactivated by peroxisome proliferator activated receptor alpha (PPARA). Upon ferroptosis induction, SLC47A1 upregulation inhibits DHA/DPA polyunsaturated fatty acid containing glycerophospholipids (PUFA-PLs) accumulation to block ferroptosis. Depletion of either PPARA or SLC47A1 sensitized cells to ferroptosis by favoring ACSL4-SOAT1–mediated production of polyunsaturated fatty acid containing (PUFA) cholesterol esters. Ferroptosis has been widely linked to degenerative processes and tumor suppression. These findings indicate that lipid transporters may provide yet another means by which PUFA-containing membrane lipids convey ferroptosis sensitivity.

Effects of Iron Valence on the Growth, Photosynthesis, and Fatty Acid Composition of Phaeodactylum tricornutum

Iron is a limiting factor that controls the phytoplankton biomass of the ocean and plays an important role in the lipid production of microalgae. Elucidating the effects of different iron valences on microalgae is helpful for their commercial production. We investigated the growth, photosynthesis, and fatty acid profile of the model diatom Phaeodactylum tricornutum cultured with depleted Fe, Fe2+, Fe2+/Fe3+, and Fe3+. Samples were taken every 24 h for 8 days, and their cell density, photosynthetic pigment content, chlorophyll fluorescence, total fatty acid content, and fatty acid composition were analyzed. The cell densities of the Fe2+ and Fe2+/Fe3+ groups were significantly higher than those of the control and Fe3+ groups (p < 0.05). They were 1.26 times and 1.23 times higher than those in the Fe-depleted group. The contents of chlorophyll a and c in the Fe2+ group were significantly higher than those in the Fe-depleted group (p < 0.05). The chlorophyll fluorescence results show that Fe2+ enhanced the photosynthesis of P. tricornutum to a greater extent than Fe3+. On the eighth day of harvest, Fv/Fm and Y(II) in the Fe2+ group were 0.672 and 0.476, respectively, being 1.10 and 1.19 times greater than those in the Fe3+ group and 1.15 and 1.33 times greater than those in the Fe-depleted group, respectively. Compared with the control group, the levels of saturated fatty acids of the Fe2+/Fe3+ and Fe3+ groups were significantly higher (p < 0.05) at 21.36 ± 1.24% and 21.20 ± 0.13%, respectively. The levels of polyunsaturated fatty acids of the Fe2+/Fe3+ group were significantly lower (p < 0.05) at 29.82 ± 2.75%. Our results show that P. tricornutum exhibited physiological plasticity, including changes in photosynthetic activities and shifts in fatty acid composition, in response to different iron valences and that Fe2+ was more beneficial to the biomass production of this species than Fe3+. These findings are applicable to the production of biomass and polyunsaturated fatty acids.